Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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SEALED SYSTEM MULTIPLE SPEED
COMPRESSOR AND DAMPING CONTROL
BACKGROUND OF THE INVENTION
This invention relates generally to sealed system refrigeration devices,
and more particularly, to controlling a damper in refrigerators.
Modern refrigerators typically include a compressor, an evaporator,
and a condenser in a closed refrigeration circuit, and a number of fans that
facilitate
the refrigeration circuit and direct cooled air into refrigeration
compartments.
Conventionally, the condenser, evaporator and condenser are operated at a
single
speed, and a plurality of single speed fans are employed in association with
the
condenser, evaporator, condenser and also to direct cooled air throughout the
refrigerator. Collectively, these components are sometimes referred to as a
sealed
system. While these single speed sealed systems have been satisfactory in the
past,
they are now perceived as disadvantageous in several aspects.
For example, such single speed systems often entail considerable
temperature variation in operation of the refrigerator as the sealed system
cycles on an
off. Further, the refrigerator can sometimes be undesirably noisy as it cycles
from an
off or relatively silent condition to an on condition with the sealed system
components
energized. In addition, single speed systems are not as energy efficient as
desired.
While most of these disadvantages can be addressed by using multiple
speed or variable speed fans and sealed system components, use of variable
speed
components has caused changes in the way refrigerators are operated. For
example, in
variable systems the duty cycle of the compressor is nearly continuous while
in single
speed systems the duty cycle is much less than nearly continuous. For example,
in
one known single speed system the duty cycle is SO%. However, a nearly
continuous
duty cycle may cause undesirable ice build up.
BRIEF DESCRIPTION OF THE INVENTION
In one aspect, a method for controlling a damper having a closed
position and an open position for providing flow communication between a first
cooled compartment and a second cooled compartment is provided. The method
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includes toggling the damper from an initial position of the damper to a
position
different from the initial position and then back to the initial position on a
periodic
basis.
In another aspect, a cooling device includes a first compartment
including a plurality of first walls and at least one first door defining a
first enclosed
volume of the first compartment and a second compartment including a plurality
of
second walls and at least one first door defining a first enclosed volume of
the second
compartment with one of the first walls. A damper is between the first
compartment
and the second compartment, the damper is movable to change an amount of flow
communication between the first compartment and the second compartment. A
sealed
system is configured to provide cooling capacity to the first compartment and
the
second compartment is operationally coupled to the first compartment and to
the
second compartment. A temperature control system is operationally coupled to
the
damper and to the sealed system. The control system is configured to toggle
the
damper from an initial position to a position different from the initial
position and
then back to the initial position on a periodic basis.
In a further aspect, a refrigerator includes a first compartment
configured to preserve food, the first compartment including a plurality of
first walls
and at least one first door defining a first enclosed volume of the first
compartment,
and a second compartment configured to preserve food coupled to one of the
first
walls, the second compartment including a plurality of second walls and at
least one
second door defining a second enclosed volume of the second compartment with
one
of said first walls comprising a damper movable to change an amount of flow
communication between the first compartment and the second compartment. A
sealed
system is operationally coupled to the first and second compartments, the
sealed
system is configured to provide cooling capacity to the first and second
compartments. A temperature control system is operationally coupled to the
sealed
system and to the damper. The control system is configured to maintain the
first
compartment at a first temperature, maintain the second compartment at a
second
temperature different from the first temperature, and toggle the damper from
an initial
position to a position different from the initial position and then back to
the initial
position on a periodic basis.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of an exemplary refrigerator.
Figure 2 is a block diagram of a refrigerator controller in accordance
with one embodiment of the present invention.
Figure 3A is a portion of a block diagram of the main control board
shown in Figure 2.
Figure 3B is a portion of a block diagram of the main control board
shown in Figure 2.
Figure 3C portion of a block diagram of the main control board shown
in Figure 2.
Figure 4 is a block diagram of the main control board shown in Figure
2.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 illustrates a side-by-side refrigerator 100 in which the present
invention may be practiced. It is recognized, however, that the benefits of
the present
invention apply to other types of refrigerators, freezers, refrigeration
appliances, and
refrigeration devices, including climate control systems having similar
control issues
and considerations. Consequently, the description set forth herein is for
illustrative
purposes only and is not intended to limit the invention in any aspect.
Refrigerator 100 includes a fresh food storage compartment 102 and a
freezer storage compartment 104. Freezer compartment 104 and fresh food
compartment 102 are arranged side-by-side in an outer case 106 with inner
liners 108
and 110. A space between case 106 and liners 108 and 110, and between liners
108
and 110, is filled with foamed-in-place insulation. Outer case 106 normally is
formed
by folding a sheet of a suitable material, such as pre-painted steel, into an
inverted U-
shape to form top and side walls of case. A bottom wall of case 106 normally
is
formed separately and attached to the case side walls and to a bottom frame
that
provides support for refrigerator 100.
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Inner liners 108 and 110 are molded from a suitable plastic material to
form freezer compartment 104 and fresh food compartment 102, respectively.
Alternatively, liners 108, 110 may be formed by bending and welding a sheet of
a
suitable metal, such as steel. The illustrative embodiment includes two
separate liners
108, 110 as it is a relatively large capacity unit and separate liners add
strength and are
easier to maintain within manufacturing tolerances. In smaller refrigerators,
a single
liner is formed and a mullion spans between opposite sides of the liner to
divide it into
a freezer compartment and a fresh food compamnent.
A breaker strip 112 extends between a case front flange and outer front
edges of liners. Breaker strip 112 is formed from a suitable resilient
material, such as
an extruded acrylo-butadiene-styrene based material (commonly referred to as
ABS).
The insulation in the space between liners 108, 110 is covered by
another strip of suitable resilient material, which also commonly is referred
to as a
mullion 114. Mullion 114 also preferably is formed of an extruded ABS
material. It
will be understood that in a refrigerator with separate mullion dividing a
unitary liner
into a freezer and a fresh food compartment, a front face member of mullion
corresponds to mullion 114. Breaker strip 112 and mullion 114 form a front
face, and
extend completely around inner peripheral edges of case 106 and vertically
between
liners 108, 110. Mullion 114, insulation between compartments 102, 104, and a
spaced wall of liners 108, 110 separating compartments 102, 104 sometimes are
collectively referred to herein as a center mullion wall 116.
Shelves 118 and slide-out drawers 120 normally are provided in fresh
food compartment 102 to support items being stored therein. A bottom drawer or
pan
122 partly forms a quick chill and thaw system (not shown) and selectively
controlled,
together with other refrigerator features, by a microprocessor (not shown in
Figure 1 )
according to user preference via manipulation of a control interface 124
mounted in an
upper region of fresh food storage compartment 102 and coupled to the
microprocessor. A shelf 126 and wire baskets 128 are also provided in freezer
compartment 104. In addition, an ice maker 130 may be provided in freezer
compartment 104.
A freezer door 132 and a fresh food door 134 close access openings to
fresh food and freezer compartments 102, 104, respectively. Each door 132, 134
is
mounted by a top hinge 136 and a bottom hinge (not shown) to rotate about its
outer
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vertical edge between an open position, as shown in Figure 1, and a closed
position
(not shown) closing the associated storage compartment. Freezer door 132
includes a
plurality of storage shelves 138 and a sealing gasket 140, and fresh food door
134 also
includes a plurality of storage shelves 142 and a sealing gasket 144.
In accordance with known refrigerators, refrigerator 100 also includes
a machinery compartment (not shown) that at least partially contains
components for
executing a known vapor compression cycle for cooling air. The components
include
a compressor (not shown in Figure 1), a condenser (not shown in Figure 1), an
expansion device (not shown in Figure 1 ), and an evaporator (not shown in
Figure 1 )
connected in series and charged with a refrigerant. The evaporator is a type
of heat
exchanger which transfers heat from air passing over the evaporator to a
refrigerant
flowing through the evaporator, thereby causing the refrigerant to vaporize.
The
cooled air is used to refrigerate one or more refrigerator or freezer
compartments via
fans (not shown in Figure 1 ). Collectively, the vapor compression cycle
components
in a refrigeration circuit, associated fans, and associated compartments are
referred to
herein as a sealed system. The construction of the sealed system is well known
and
therefore not described in detail herein, and the sealed system components are
operable at varying speeds to force cold air through the refrigerator subject
to the
following control scheme.
Figure 2 illustrates an exemplary controller 160 in accordance with one
embodiment of the present invention. Controller 160 can be used, for example,
in
refrigerators, freezers and combinations thereof, such as, for example side-by-
side
refrigerator 100 (shown in Figure 1 ).
Controller 160 includes a diagnostic port 162 and a human machine
interface (HMI) board 164 coupled to a main control board 166 by an
asynchronous
interprocessor communications bus 168. An analog to digital converter ("A/D
converter") 170 is coupled to main control board 166. A/D converter 170
converts
analog signals from a plurality of sensors including one or more fresh food
compartment temperature sensors 172, a quick chill/thaw feature pan (i.e., pan
122
shown in Figure 1 ) temperature sensors 174, freezer temperature sensors 176,
external
temperature sensors (not shown in Figure 2), and evaporator temperature
sensors 178
into digital signals for processing by main control board 166.
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In an alternative embodiment (riot shown), A/D converter 170 digitizes
other input functions (not shown), such as a power supply current and voltage,
brownout detection, compressor cycle adjustment, analog time and delay inputs
(both
use based and sensor based) where the analog input is coupled to an auxiliary
device
(e.g., clock or finger pressure activated switch), analog pressure sensing of
the
compressor sealed system for diagnostics and power/energy optimization.
Further
input functions include external communication via IR detectors or sound
detectors,
HMI display dimming based on ambient light, adjustment of the refrigerator to
react
to food loading and changing the air flowlpressure accordingly to ensure food
load
cooling or heating as desired, and altitude adjustment to ensure even food
load cooling
and enhance pull-down rate at various altitudes by changing fan speed and
varying air
flow.
Digital input and relay outputs correspond to, but are not limited to, a
condenser fan speed 180, an evaporator fan speed 182, a crusher solenoid 184,
an
auger motor 186, personality inputs 188, a water dispenser valve 190, encoders
192
for set points, a compressor control 194, a defrost heater 196, a door
detector 198, a
mullion damper 200, feature pan air handler dampers 202, 204, and a quick
chill/thaw
feature pan heater 206. Main control board 166 also is coupled to a pulse
width
modulator 208 for controlling the operating speed of a condenser fan 210, a
fresh food
compartment fan 212, an evaporator fan 214, and a quick chill system feature
pan fan
216.
Figures 3A, 3B, 3C (collectively referred to as Figure 3), and 4 are
more detailed block diagrams of main control board 166. As shown in Figures 3
and
4, main control board 166 includes a processor 230. Processor 230 performs
temperature adjustments/dispenser communication, AC device control, signal
conditioning, microprocessor hardware watchdog, and EEPROM read/write
functions.
In addition, processor 230 executes many control algorithms including sealed
system
control, evaporator fan control, defrost control, feature pan control, fresh
food fan
control, stepper motor damper control, water valve control, auger motor
control,
cube/crush solenoid control, timer control, and self test operations.
Processor 230 is coupled to a power supply 232 which receives an AC
power signal from a line conditioning unit 234. Line conditioning unit 234
filters a
line voltage which is, for example, a 90-265 Volts AC, 50/60 Hz signal.
Processor
230 also is coupled to an EEPROM 236 and a clock circuit 238.
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A door switch input sensor 240 is coupled to fresh food and freezer
door switches 242, and senses a door switch state. A signal is supplied from
door
switch input sensor 240 to processor 230, in digital form, indicative of the
door switch
state. Fresh food thermistors 244, a freezer thermistor 246, at least one
evaporator
thermistor 248, a feature pan thermistor 250, and an ambient thermistor 252
are
coupled to processor 230 via a sensor signal conditioner 254. Conditioner 254
receives a multiplex control signal from processor 230 and provides analog
signals to
processor 230 representative of the respective sensed temperatures. Processor
230
also is coupled to a dispenser board 256 and a temperature adjustment board
258 via a
serial communications link 260. Conditioner 254 also calibrates the above-
described
thermistors 244, 246, 248, 250, and 252.
Processor 230 provides control outputs to a DC fan motor control 262,
a DC stepper motor control 264, a DC motor control 266, and a relay watchdog
268.
Watchdog 268 is coupled to an AC device controller 270 that provides power to
AC
loads, such as to water valve 190, cube/crush solenoid 184, a compressor 272,
auger
motor 186, a feature pan heater 206, and defrost heater 196. DC fan motor
control
266 is coupled to evaporator fan 214, condenser fan 210, fresh food fan 212,
and
feature pan fan 216. DC stepper motor control 266 is coupled to mullion damper
200,
and DC motor control 266 is coupled to one of more sealed system dampers.
Periodically, controller 160 reads fresh food compartment thermistors
244 and freezer thermistor 246 to determine respective temperatures of fresh
food
compartment 102 (shown in Figure 1 ) and freezer compartment 104 (shown in
Figure
1 ). Based on the determined temperatures of compartments 102, 104, controller
160
makes control algorithm decisions, including selection of operating speed of
the
various sealed system components, as described below.
Additionally, mullion damper 200 is toggled on a periodic basis to
prevent frost buildup that may impair movement of mullion damper 200 or
prevent
proper operation thereof. That is, when the damper is in a closed position it
is toggled
to an opened position and returned to the closed position, and when the damper
is in
an opened position it is toggled to the closed position and returned to the
open
position. In an exemplary embodiment, damper 200 is toggled at thirty minute
intervals. In alternative embodiments, however, damper 200 may be toggled more
regularly or less regularly. For example, damper is toggled periodically with
a
periodicity of between approximately 10 minutes and approximately 60 minutes,
with
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a periodicity between approximately 15 minutes and approximately 45 minutes,
with
a periodicity between approximately 25 minutes and approximately 35 minutes,
with
a periodicity between approximately 15 minutes and approximately SO minutes,
with
a periodicity between approximately 20 minutes and approximately 40 minutes,
or
with a periodicity between approximately 25 minutes and approximately 35
minutes.
Additionally, toggling may occur the same or different time that compartment
temperatures are read or control parameters are adjusted. Also toggling is
both done
during a defrost mode in which the temperature of freezer compartment 104 is
allowed to warm up, and during a cooling mode in which one or both of freezer
compartment 104 and fresh food compartment 102 are being cooled.
By toggling damper 200 on a periodic basis, any ice that builds up on
damper 200 and/or damper gears (not shown) is broken up and does not allow a
substantial amount of ice build up such that damper 200 is frozen in one
position and
no longer moveable. Accordingly, a cost effective refrigerator is provided
that is long
lasting and has an improved damping system over known damping systems.
While the invention has been described in terms of various specific
embodiments, those skilled in the art will recognize that the invention can be
practiced
with modification within the spirit and scope of the claims.
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